Presence of melanin in melanin containing cell line - (Nov/15/2012 )
We are culturing MeWo (Human malignant melanoma) cells in DMEM:F12 (1:1 mixture) supplemented with 2 mM L-glutamine and 10% fetal bovine serum. We grow cells in a 5% CO2 atmosphere. When I examine cell culture flaks under a microscope, I cannot see melanin pigmentation. Is it normal? I supposed to see dark granular material. How can I stimulate melanin synthesis in these cell line without killing cells?
There are a few things you could check - first of all would be to ensure that the cells are actually MeWo (it is estimated that about 30% of cell lines in laboratories are not actually the cell line the users think they are) - you will need to do some isozyme analysis for this or pay for a cell line validation. Also, compare your cells with someone else's in the lab/institute.
You can also check the cells on a slide rather than in the medium, which may be absorbing some of the light needed to distinguish the melanin.